Telematics units are known and may be used to track and monitor vehicles such as cars, motorcycles, vans and trucks. The telematics unit is mounted in the vehicle and gathers information about the status of the vehicle. The telematics unit may then either store the information for later retrieval, or report the information to a remote monitoring station using a mobile communications network.
An exemplary telematics unit may contain a Global Positioning System (GPS) unit, a connection to a vehicle network (such as a Controller-Area Network or CAN) and a connection to a user interface. The GPS unit provides speed and position data, the connection to the vehicle network provides engine status, speed and fault data from the electronic control units (ECUs) of the vehicle, and the user interface enables interaction with the driver of the vehicle. The telematics unit also contains a mobile communications transceiver which communicates with a controlling station and may send the data received through these connections to the controlling station.
Recently, it has been proposed to fit accelerometers into the telematics units and to send, store or use the accelerometer data along with other telematics data. However the difficulty in implementing such a system is that the accelerometer needs to be carefully mounted in the vehicle for the accelerometer data to have meaning. That is, the accelerometer needs to be accurately mounted in a specific orientation relative to the vehicle so that the orientation of the accelerometer data is aligned with the vehicle.
This can be difficult because a technician must take care when installing the telematics system to ensure it is aligned with the vehicle. Equally, this requirement for alignment can severely restrict the potential locations for mounting the telematics device compounding the problems in mounting the telematics unit.
There is therefore a need for a system and method which enables an accelerometer connected to a telematics device to be easily mounted to a vehicle and which enables the accelerometer data to be interpreted such that the direction of the acceleration of the vehicle is known.